Ex-situ machine perfusion devices for deceased donor liver transplants

3 Current practice

People identified as needing a liver transplant are placed on a waiting list. The waiting list operates like a matching system, where a donor liver is allocated to the person most likely to gain the greatest benefit from that particular donated organ. The national UK median waiting time for an elective liver only transplant from a deceased donor is about 5 months in adults and 3 to 4 months in children, but this varies across transplant centres (NHS Blood and Transplant, 2024b).

Within the NHS, transplants are done by specialist liver transplant surgeons in 7 centres for adults and 3 centres for children across the UK.

In the UK, the majority of livers that are suitable for transplantation come from donors who have died. In 2023/24, 99% of adults and 72% of children who underwent liver transplantation received livers from deceased donors (NHS Blood and Transplant, 2024a). The remainder received liver transplants from living donors.

Standard care for liver transplant involves removing the liver from deceased donors after either brainstem death (DBD) or circulatory death (DCD) The use of DCD livers is more common in adults than in children.

In adults, the majority of donated livers are transplanted as a whole organ. In children, split liver transplants are more common. This is because children require smaller grafts and there is a limited supply of whole livers from deceased paediatric donors. Split livers are usually obtained from carefully selected low-risk donors. According to experts, liver splitting is usually done at paediatric liver transplant centres. The smaller left lobe is transplanted into a child or small adult. If usable, the larger right lobe may be transported to an adult liver transplant centre and used for an adult.

A donor liver for transplant is usually preserved using static cold storage. This involves flushing the donor liver with cold organ preservation solution and then placing it in a sterile bag in a cold storage icebox for transport. This is done by a specially trained team before the donor liver is transferred to the selected hospital for transplant as soon as possible, to minimise ischaemic damage to the organ. Livers are usually stored for a maximum of 8 to 12 hours in an icebox before transplantation.

Increasingly, organ retrieval teams do in-situ normothermic regional perfusion (NRP) before abdominal organs are removed from donors after circulatory death. In this procedure, instead of immediately cold-flushing the organs, the donor is first connected to a machine which perfuses the abdominal organs with an oxygenated blood supply for about 2 hours. This process helps make abdominal organs better able to withstand the subsequent cold storage process and increases their chances of working well after they are transplanted. During NRP, the function of the liver can be assessed.

According to NICE interventional procedures guidance 636 (2019), use of ex-situ machine perfusion devices for liver transplants is by special arrangement only. In the UK, ex-situ machine perfusion technologies are usually initiated at the hospital of the person having the transplant after the liver has been transported using static cold storage. The use of ex-situ machine perfusion technologies varies across UK liver transplant centres, in terms of which technologies are used, how often they are used, the circumstances they are used for and how they are funded. The use of ex-situ machine perfusion for liver transplants is more common in adults than in children.

A list of related NICE guidance can be found in appendix B of this document.